1. Field of the Invention
This invention relates generally to recording and reading data from magnetic storage media and, more particularly, to servo format verifier heads to verify servo patterns used to maintain the position of a magnetic head relative to tracks in magnetic storage media.
2. Description of the Related Art
The recording and reading of data in tracks on magnetic storage media requires precise positioning of magnetic read/write heads. The read/write heads must be quickly moved to, and maintained centered over, particular data tracks as recording and reading of data takes place. The magnetic heads can record and read data as relative movement occurs between the heads and the magnetic storage media in a transducing direction. The heads are moved from track to track across the width of the tracks in a translating direction, which is perpendicular to the transducing direction.
For example, a recordable disk typically contains concentric data tracks and is rotated beneath a magnetic head. The direction of rotation defines the transducing direction. Radial movement from track to track defines the translating direction. A magnetic tape typically contains data tracks that extend along the length of the tape, parallel to the tape edges, in the transducing direction. In magnetic tape helical scan systems, however, the tape is moved beneath heads that are moved at an angle across the width of the tape, the diagonal direction defining the transducing direction.
Storage devices that read and record data on magnetic media typically use servo control systems to properly position the data heads in the translating direction. The servo control systems derive a position signal from a servo magnetic head that reads servo control information recorded in servo tracks on the storage media. A track following servo control system in a magnetic media storage device derives head position information from one or more specially patterned servo tracks. The servo patterns are comprised of magnetic transitions recorded at more than one azimuthal orientation in a servo track, such that the timing of the servo position signal pulses derived from reading the servo pattern at any point on the pattern varies continuously as the head is moved across the width of the servo track.
Servo control systems that maintain the position of a magnetic head relative to tracks in magnetic storage media are well known. European Patent Application EP 0 690 442 A2, published Jan. 3, 1995, entitled “Servo Control System”, Albrecht et al., describes a servo control system having a magnetic recording head for writing servo position code at discrete locations across the width of the magnetic recording tape and down the length of the tape. The advantage of such a recording head is the ability to write servo code along the entire length of the tape in discrete areas (bands) across the width of the tape in a single pass. This increases position accuracy of one pattern with respect to another.
It is often necessary to verify that a servo format pattern has been properly written on tape magnetic media. One method of verification is to use a tape head's servo read transducer elements to verify the servo format patterns, however this method only monitors a few bands of the servo format. A special version of a regular tape head specifically tailored to the servo format verification process could be designed, developed and fabricated, however this approach involves considerable development and cost.
Therefore, an unresolved need exists for a magnetic head that provides the desired servo format verification function that can be developed and manufactured efficiently at a reduced cost.